Sheet metal forming machines



Oct. 6, 1964 R. BERANEK 3,151,657

SHEET METAL FORMING MACHINES Filed March 22, 1961 3 Sheets-Sheet 1 INVEN TOR. RUDOL PH HERA NE K BY MAHONEY. MILLER & RAMBO A TTORNEYS.

Oct. 6, 1964 R. BERANEK 3,151,657

,SHEET METAL FORMING MACHINES Filed March 22, 1961 3 ShegEs-Sheet 2 INVEN TOR. RUDOLPH HERA NEK BY 4! MAHONEY. M/LLER8 RA B0 AT TORNE Y5.

Oct. 6, 1964 R. BERANEK SHEET METAL FORMING MACHINES Filed March 22,1961 3 Sheets-Sheet 3 IN V EN TOR. RUDOLPH BERA NE K BY MAHONEY, MILLER& RAMBO 7 5y km 4% ATTORNEYS.

United States Patent O 3,151,657 SHEET METAL FQRMING MACHlNES RudolphBeranelr, Columbus, Ohio, assignor to United Sheet Metal Co., Inn,Eolnmhus, Ghio, a corporation of @hit) Filed Mar. 22, 1961, Ser. No.97,501 3 Claims. (Cl. 1532l) This invention relates to sheet-metalforming machines and to a method of forming parts thereon and, moreparticularly, to new and useful improvements in a spinning machine forforming parts from lightweight sheet-metal pipe and to a method ofintegrally forming tubular sheetmetal T-fittings.

It has been the usual practice to fabricate tubular sheetmetalT-fittings of the type commonly utilized in heating and ventilating orair conditioning systems by welding a short cylindrical flange to theouter wall surface of a main tubular body section forming a lateralextension thereof. This method necessitates the precise cutting of acircular opening in the tubular wall of the main body sectioncorresponding in size to the desired laterally eX- tending cylindricalflange. An obvious major difilculty encountered is in the cutt ng ofthis opening which is further increased. when the main tubular bodysection is also cylindrical as the opening is then irregularly shaped.In the latter instance, the end of the cylindrical flange welded to themain body section must also be arcuately cut to conform with thecylindrical surface to provide an intersection capable of being welded.Another inherent disadvantage of this method of fabrication is thata'highly skilled technician is requ red to perform the Weldingoperation. As a consequence of the numerous and difficult operationsinvolved in the above-described method of fabrication, an excessiveamount of time and labor is utilized resulting in a correspondinglylarge cost per unit. Also, the performance of T-fittings fabricated inaccordance with the above-described method has con found to beunsatisfactory when utilized for the transmission of fluids in heatingand ventilating or air conditioning systems. This results from the sharpcorners formed at the intersection of the main body section and thelaterally extending flange which disrupt the laminar fluid flow patternand unnecessarily impede the transmission of fluids thereby reducing theeficiency of such T-iittings and correspondingly increasing their costof operation. Therefore, it is the primary object of this invention toprovide a spinning machine and method for the rapid and economicalfabrication of T-ittings from tubular sheet-metal pipe and to provide anintegrally formed tubular sheet-metal T- fitting having superior fluidtransmission characteristics resulting from a smooth, roundedintersection.

A further object of this invention is to provide a spinning machinehaving a rotatable spinning tool and a shaping mandrel readily adaptablefor use on a vertical mill or radial drill wherein the spinning tool isinserted in a pre-cut or pre-punched hole in the wall of a cylindricalsheet-metal tube and thereafter withdrawn as it is rotated integrallyforming a T-fitting.

In the preferred embodiment of this invention the spinning machine forfabricating tubular sheetmetal T-fitt'ngs has a rotatable spinnim toolcomprising a radial arm, rotatable about an axis at one end thereof,supporting an inclined spinning roller assembly adjustablelongitudinally with respect to the radial arm and thereby capable of acconm-ioclating a varying range of T-fitting sizes and having asupporting and shaping mandrel assembly for precisely and securelypositioning a T-fitting blank with respect to the spinning tool.

The accompanying drawings illustrate the present preferred embodiment ofthe spinning machine of this invention, the method accomplished with itand the resulting product.

in these drawings:

FIG. 1 is a front vertical view of a spinning machine embodying thepresent invention;

FIG. 2 is a horizontal sectional view of a spinning machine showing thetable, mandrels and spinning tool thereof taken on line 2-2 of FIG. 1; a

FIG. 3 is a vertical sectional detail of the mandrels and spinnin g tooltaken on line 3--3 of PEG. 4;

FIG. 4 is a vertical sectional detail of the mandrels and spinning tooltaken on line 4-4 of FIG. 3;

Phi. 5 is a diagrammatical vertical sectional detail showing thespinning tool positioned within the mandrels and a sheet-metal tubingblank clamped between the mandrels;

FIG. 6 is a diagrammatical vertical sectional detail showing thespinning tool operating on a partially formed T-itting;

FI 7 is a diagrammatical vertical sectional detail showing the spinningtool finishing the upturned annular flange of a T-fitting;

FIG. 8 is a perspective view of a sheet-metal tube blank with apre-punched starting hole; and

FIG. 9 is a perspective view of a completed T-fitting made with apreferred embodiment of the spinning machine and according to the methodof this invention.

Referrin to the drawings, particularly FIG. 1, the present embodiment ofthe spinning machine of this invention com rises in general a verticalmilling machine ll? having a vertical supporting standard 11, a millhead 12 vertically disposed and rigidly mounted on the standard 11 atthe upper end 13 thereof, a horizontally disposed work-supporting table7.4 mounted on the standard 11 at the lower end 15 thereof and movableboth horizontally and vertically, and a spinning tool 16 rotatablymounted on the mill head 12. The present embodiment of this invention isadvantageously adapted to a common vertical milling machine as the table14 of such a machine is conveniently adjustable in three directions,that is, longitudinally and transversely in a horizontal plane, andvertically toward and away from the mill head 12, for preciselypositioning a tubular, sheet-metal pipe blank 17 relative to thespinning tool 16. However it is contempla'ted that the present inventionmay also be readily adapted for use on a radial drill or other similarmachines equally capable of providing the required rotational motion ofthe spinning tool and of precisely positioning a T- tting blank 17 andspinru'ng tool relative to each other.

The spinning tool 16, as is best shown in FIGS. 1, 3 and 4, comprises aradial arm 18, a mounting shaft 1? and a spinning roller structure 29.The radial arm 18 is of an elongated rectangular bar configurationhorizontally disposed and parallel to the surface of the table 14.Rigidly arllxed to the upper horizontal surface 21 of the radial arm 18at a point intermediate of its ends 22 and 23, is the verticallydisposed, cylindrical mounting shaft 19 of a diameter suitable forinsertion in the chuck on the usual type of tool spindle 24 incorporatedin the mill head 12. The spinniru roller structure 2% is slidablymounted on the lower horizontal surface 25 of the arm 18 and is capableof longitudinal adjustment to increase or decrease its radial distancefrom the central vertical axis of the mounting shaft 19. All componentsof the spinning tool 16 are constructed of steel appropriately hardenedfor the specific utilization.

In the present embodiment, the radial arm 18 is conveniently fabricatedas a composite structure to obtain a more satisfactory structuralstrength and to utilize more economical machining operations. The basicstructure of the radial arm 18 consists of an elongated rectangular bar26 with the shaft 1? affixed to its upper horizontal relationship withthe lower horizontal surface .25. pivot bolt 35 extending verticallythrough the cam 33 at .cam one-half revolution about. its eccentricaxis.

the bar 26, vertically disposed, flat rectangular plates 28 and28a arerigidly attached, respectively, as for example, by the bolts 29. Eachplate 28 and 23a extends substantially the length of the bar 26 and isof a widthv greater than the sides 27 and 27a of the bar 26 to extendbelow the lower horizontal surface 25 andform an open-bottom channeltherewith. A flange 39 and 30a is integrally formed along. the lowerlongitudinal marginal edges 31 and 31a of the plates 28 and 28::extending laterally toward the center of the radial arm 18 therebyrestricting the open-bottom channel to a cross-sectional T-shape. Trans-1 versely across one end 22 of the bar 26, a flange 32 is integrallyformed extending vertically downwardly from mounted on a base 34 of thecylinder in a contacting 'A its eccentric axis is threadedly engagedwith the radial V 4 i tool 16. The opposite or lower end 48 of thespindle 33 has an integrally formed flange 49 laterally disposed andextending around the circumference of the spindle.

to provide a thrust bearing surface 51 for the roller 39. The roller 39is an elongated cylinder with a. central longitudinal bore extendingthrough the cylinder and is rotatably positioned on the spindle 38. Thelower end 51 of the roller 39 is in a contacting relationship with theflange 4? and has a smooth machined bearing surface formed thereon. 'Thecorner at the juncture-of the end 51 and the cylindrical surface of theroller'39 is formed with a small radius. The upper end 52 of the roller39 is arcuately curved forming a hemispherical surface.

arm 18. The diameter of the cam and its degree of a eccentricity aredetermined by the length of offset or longitudinal motion required forproper adjustment of the roller structure 20 with respect to themounting shaft 19. If necessaryffor the specific application, the sideplates 28 and 28a may be accordingly cut out to readily accommodate theparticular cam size utilized. The cam 33 is advantageously mounted topermit the maximum and minimum positions to be attained by rotating theA handle 36 is rigidly attached to the cam 33 on its cylindrical surfaceto facilitate its operation, Although'a circular ca'mhas been describedto obtain the necessary retilinear adjustment, it is to be understoodthat other mechanisms may be utilized equally well; For purposes ofillustration, it is contemplated that an irregularly shaped cam or afeed screw mechanism; or a system of indexing pins and associated holeswould prove equally suitable.

-, The spinning roller structure'20, comprising a mounting block 37, aspindle 38 and a spinning roller 39, is

slidably mounted on the lower horizontal surface of. the radial arm 18by the T-channel previously described.

The mounting block 37 is rectangularly shaped with'the upper portion 40,which is engaged by the radial arm 18,

being provided with integrally formed flanges 41 and 41a 1 extendinglaterally from the sides 42 and 42a and longitudinally-disposed alongthe upper portion 40"thereby forming a cross-sectional T-shapecorresponding to that V of the T-channel on the radial arm 18 as isshown by FIG.

3. The upper portion 46] of the mounting block 3'? with 'its associatedflanges 41 and 41a is slidably engaged by lower surface 44 with theinclination being upwardly toward the radial arm 18 and outwardly towardthe flange '32.. A cylindrical hole 45 is bored in the central portionof the inclined surface 44 and perpendicular thereto for reception ofthe end 46 of the elongated cylindrical spinning roller spindle 39. Aset screw 47, as shown by FIG. 4, is conveniently utilized by thepresent embodiment to rigidly secure the spindle 38 in its associatedhole 45. The sphidle 33 is of course perpendicularly positioned withrespect to the inclined surface 44 to provide the predeterminedinclination of the spinning roller 39 with respect to the vertical axisof the spinning intermediate the block 37 and the flange 32 on the bar 26 and within the area defined by the aforementioned T.- channel arearranged a multiplicity of compression springs 53, ofwhich only one isshown in FIGS. 1 and 4, extending longitudinally of the radial arm 18and being in an end contacting relationship with the flange 32 and theblock 37. The length of the compression springs 53 are accordinglydetermined by the distance between the flange 32. and the block 37 tomaintain the block 37in a contacting relationship with the cylindricalsurface of the cam 33 at all times. been found advantageous toutilizethree compression springs but the number may be varied as is dictated bythe resilient characteristics of the particular springs utilized.Elongated, cylindrical, retaining pins 54, or guide pins, only one beinshown on the drawings, of a diameter slightly smaller than the internaldiameter of the springs are coaxially positioned within the springs 53.Each pin 54 longitudinally extends beyond the springs with the endportions 55 inserted within the correspondingly sized holes drilled inthe adjacent vertically disposed side 56 of the block'37. The pins 54,in the present embodiment,

arerigidly secured to the block 37 by the convenient holes 58, of whichonly one is shown in FIG. 4, located 7 in the flange 32 and extendingentirely through the flange parallel to the longitudinal axisof theradial arm 18I This completes a detailed description of the spinningtool as illustrated by the present embodiment. Although the spinningtool described utilizes only one spinning roll er, it is contemplatedthat necessary modifications may be 7 made to utilize at least oneadditional roller (not shown),

similar to the one herein described, positioned diametrically oppositeon a longitudinal extension of the radial arm. Such a multiple rollerarrangement would be par ticularly advantageous in forming largediameter T-fittings as the forces encountered in the spinning operationwould be counterbalanced thereby reducing the resultant stresses. Thespinning operationwould also be improved as a multiple roller tool couldbe rotated at an increased speed with a consequent reduction of timeconsumed to complete the spinning operation and a decreased cost ofproduction. a a

The sheet-metalpipe supporting mandrel 59 is an open ended, invertedU-shaped channel positioned with its longitudinal axis parallel to thatof the table 14. The top portion cc of the mandrel 59 is arcuatelycurved in a transverse direction forming a cylindrical surface, as isbest shown by FIG. 3, for the internal support of a tubular pipe blank17. As a pipe blank 17 is placed over 7 the mandrel 59, the radialdimensionof the arcuately curved top portion 60 is determinedby thediameter of the smallest sheet-metal pipe to be utilized in conjunctionwith a specific support mandrel as is its length. However, largerdiameter sheet-metal pipes mayalso be satisfactorily supported by thesame mandrel as it is not necessary that a supporting surface be incontact with more than a small arcuate segment of a tubular pipe wall.

In the present embodiment, it has' Each longitudinal marginal edge 62and 63 of the armately curved top portion terminates in straight,vertically disposed side portions 64 and 65. A section is cut out of themandrel 59 at the central portion intermediate its ends 66 and 67forming a generally circular opening 68 having its central axisvertically disposed to the longitudinal surface of the mandrel 59 andhaving communicating downwardly extending notches 68a. It will be notedthat the circular opening es is formed in the armately curved topportion of the mandrel and the notches fizz are formed in the sideportions 64 and of the manrh'el. The dimeter of the cylindrical opening68 is sufficiently large to provide adequate clearance for rotation ofthe spinning tool 16 when it is inserted within the mandrel and thecommunicating notches 68a cooperate in providing such clearance. Acrosseach open end 66 and s7 of the mandrel 59, horizontally disposedrectangu lar bars 69 and 6941 are rigidly attached, as for exmple bywelding, interconnecting the vertical side portions 64 and 65 but notextending outwardly beyond such portions to provide a supportingabutment external to the main body of t-Lfi mandrel. Equally dimensionedremovable rectangular support blocks 7%) and 7% are disposed between thebars 69 and 69a and the table 14 to maintain the mandrel 59 at apredetermined distance above the table 14 to provide suficient clearancefor sheet-metal pipe bi k 17 positioned on the mandrel.

The tubular sheet-metal pipe clamping and shaping mandrel 71 is an openended, inverted semicircular channel, the internal radius of which isgreater than the external radius of the arcuate top portion 66 of thesupporting mandrel 59, and which is concentrically positioned over suchtop portion of the mandrel 59. As this mandrel 71 is utilized in shapingthe laterally extending flange of a T-fitting, its internal radius mustcorrespond to that of the pipe blank 17 with which it is utilized and amandrel must be designed for each specific size pipe blank 17 that willbe utilized. The length of the mandrel 71, of course, need only besufficiently greater than the diameter of the laterally extending flangeof the T-iitting to be formed to provide an adequate clamping surface.In the central portion of the mandrel 71 intermediate its ends 72 and72a, a circular opening 635, having its central axis vertically disposedto the longitudinal surface of the mandrel, is formed which coincideswith the central vertical axis of the c rcular opening 68 in thesupporting mandrel 59. A cylindrical flange 73 laterally extending fromthe external cylindrical wall 74 of the mandrel 71 is disposed aroundthe circular opening 6812 providing a shaping mandrel for the laterallyextending flange of the T-fitting to be fabricated. The intersection ofthe cylindrical flange 73 and the inner cylindrical surface 75 of themandrel 71 is constructed with a radial corner 73a to avoid an abruptchange in cross-section from the main longitudinal body of the mandrelto the laterally extending flange 73.

The work-supporting and clamping mandrels 59 and 71, as shown in FIGS. 1and 2, are positioned on and removably secured to the mill Work table 14by appropriately positioned clamps of the type commonly used fortemporary machine set ups. That is, T-head bolts 7 6 of suitable lengthare positioned in the T-slots 77 of the table 14 adjacent to themandrels to provide the required clamping force. Rectangular clampingbars 73 are engaged at a point intermediate their ends by the bolts 76and secured thereto by nuts 79 cooperatively threaded on one end of thebolts. One end of the bars 78 are in contacting engagement with thecross bars 69 and 69a of the mandrel 59 and the external surface 74 ofthe mandrel 71, with which they are respectively associated. Theopposite or outer ends of the bars 78 are supported by removablerectangular blocks 39 and 81 which are of a height equal to that of themandrels 59 and 71 respectively. T ightening the nuts 79 draws the bars73 into engagement with 6 their respective mandrels securing theassembly to the table 14.

The tubular sheet-metal pipe blank 17 utilized in forming the finishedarticle with the present embodiment of the spinning machine comprises anelongated tubular main body section 82 as shown by FIG. 8 with itsdiameter and length being determined by the physical dimensions of thedesired finished article. A slot 83 is cut or punched in the cylindricalwall of the body section 82 at a point intermediate the ends 84 and 85thereof to remove the excess metal which is not required in theformation of the laterally extending flange and to provide an opening inwhich to insert the spinning tool 16 for the spinning process. The slot83 is an elongated slot with arcuate end portions 86 and 87 of equalcurvature interconnected by the parallel straight sides 83 and 89tangential to the arcuate end portions 86 and 87. The slot 83 islongitudinally disposed with respect to the body section 82 providing alarger amount of metal for formation of the cylindrical side portions ofthe laterally extending flange laterally disposed from the centrallongitudinal axis of the slot 83.

A tubular sheet-metal T-fitting 9i fabricated in accordance with themethod of this invention and utilizing the present embodiment of thespinning machine comprises a main body section 91 with a laterallyextending cylindrical flange 92 as is illustrated by FIG. 9. The mainbody section 91 consists of an elongated cylindrical sheet- 1 etal pipehaving a circular opening 93 in the cylindrical wall positionedintermediately of its ends 94 and 95. Annularly disposed around theopening 93 is the cylindrical flange 92 laterally extending from themain body section $1 with its open end 9% uniformly disposed from thecentral longitudinal axis of the main body section 91. The flange 92 isintegrally formed with the main body section 91 with the annularintersection 97 therebetween axially curved with respect to the centralvertical axis of the flange 92 presenting a smooth rounded transitionfrom the internal cylindrical surface of the main body section 91 to theinternal cylindrical surface of the flange 92.

To fabricate a T-fitting of the form illustrated in PEG. 9 utilizing thepresent embodiment of the spinning machine, a tubular sheet-metal blank17 is positioned between the mandrels 59 and 71 with the shaft 19 of thespinning tool 16 centrally aligned in the mandrel openings. Rotating theshaft 19 revolves the roller 39 about the axes of the mandrel openingsto spin the flange 92 in conformance with the laterally extended flange73 of the mandrel 71. For purposes of properly mounting the blank 17 onthe mandrels, it is necessary to remove mandrel 71 which is readilyaccomplished by removing the clamping bars 78 associated therewith. Theclamping bar '78 and the supporting block 70 associated with cross bar69 are also removed to permit the blank 17 to be placed on the mandrel59. The mandrel 71 is then replaced, as are the clamps previouslyremoved, with the openings in the mandrels 59 and 71 and the slot 83concentrically aligned. The table 14 of the mill 12 with the attachedmandrel assembly is then horizontally and vertically adjusted toposition the roller 39 of the spinning tool within the aligned openingsof the mandrels 559 and 71 and the blank 17. Initially positioning thespinning roller structure 20 at its minimum radius by the cam 33, poweris applied to the mill head 12 causing the mill head spindle 2 4 withthe spinning tool shaft 19 inserted therein to rotate and the table 14is gradually lowered bringing the peripheral edges of the slot 83 intocontact with the cylindrical surface of the roller 39 near its upper end52 as illustrated by FIG. 5. Further lowering the table 14 causes thecylindrical wall of the blank 17 to be spun upwardly into thecylindrical area defined by the flange 73 of the mandrel 71 as theradius of the revolving movement of the roller 39 contacted by the blank17 is gradually increased as a consequence of the inclination of theroller 39. FIG. 6 illustrates a partially formed or upset flange portion92a. Loweringthe table 14 still further brings the radial corner at thelower end 51 of the roller 39 into contact with the blank 17, asindicated by FIG. 7, spinning the flange to its final shape indicated at92 which corresponds to the shape of the internal cylindrical sur faceof the flange 73. This completes the spinning operation andthefabrication of a tubular sheet-metal T-fltting 90 and the T-fitting maythen be removed from the mandrels .59 and 71 by removing the clamps andthe mandrel 71. If a larger diameter flange 92 is desired, the radialposition of the spinning roller structure is increased 'by rotating thecam 33 toward its maximum position and repeating the spinning operation.In this instance, an appropriate larger diameter flange 73 on themandrel 71 must also be used for the initial spinning operation. As analternative method, provided the sheet metal utilized in the fabricationof the blank has the required ductility, the initial spinning operationwith the spinning roller struc ture 20 adjusted to its minimum radiusmay be eliminated and a larger appropriate radius may be used to revolvethe rollerthrough a path appropriate to produce a flange tioned with itsaxis eccentrically located therein and the' roller is revolved vbodilythrough a path which extends beyond the area of the opening so as toupset the metal at the edge of the opening to form the upstandingflange. The upsetting operation may be performed all at once or theextent of the revolving path of the roller may be gradually increased toprogressively upset the metal adjacent'the opening so as to graduallyform the flange.

It can be readily seen that the fabrication of tubular sheet metalT-fittin s as illustrated by FIG. 9 is greatly facilitated by theutilization of a spinning machine as herein described. The presentembodiment greatly reduces the separate operations required and inparticular the costly time and labor-consuming cutting and Weldingoperations. Central manufacturing plants can, therefore, advantageouslyproduce the various sizes of T-fittings commonly utilized in heating andventilating or air conditioning systems with a consequent reduction ofcost as. compared with the more usual field fabrication methodspreviously described. In addition, T-fittings fabricated in accordancewith the method of this invention possess superior fluid transmissioncharacteristics as a consequence of integrally forming the laterallyextending flange with the main body section with a gradually roundedmerging intersection. This greatly reduces the impedance to the fluidflow increasing the efliciency of systems utilizing such T-fittings andthereby lowering their cost of operation.

According to the provisions of the patent statutes, the principles ofthis invention have been explained and have been illustrated anddescribed in what is now considered to represent the best embodiment.However, it is to be understood that, within the scope of the appendedclaims,

the'invention may be practiced otherwise than as specificallyillustrated and described.

7 Having thus described this invention, What is claimed is: 1. Aspinning machine for the fabrication of tubular sheet metal T-fittingscomprising a spinning head attached to a vertical supporting standardanda work supporting table mounted on the said vertical supportingstandard, said spinning head having a spinning tool rotatably l 5mounted thereon by a vertically disposed mounting shaft, said spinningtool having an arm radially extending from said mounting shaft and acylindrical spinning roller angularly disposed to said arm, said rollerextending downwardly from said arm and outwardly from the centralvertical axis of said mounting shaft, said roller also beinglongitudinally slidably mounted on said arm and freely rotatable aboutits inclined axis, said work supporting table and said spinning headbeing movable vertically relatively, said table having removablyattached thereto an elongated longitudinal tubular work supportingmandrel with an annular opening vertically positioned there nintermediate its ends, sa d table also having an elongated semicircularclamping mandrel positioned on the supporting mandrel and having anupstanding cylindrical shaping flange vertically disposed to saidmandrel, said clamping mandrel,

being positioned over said supporting mandrel with said opening in thesupporting mandrel and the flange of said clamping mandrelconcentrically aligned with the vertical axis of the said mountingshaft.

2. A spirming machine for the fabrication of hollow sheet metalT-fittings comprising a spinning head attached to a supporting standardand a work-supporting table mounting on the supporting standard, saidspinning head having a spinning tool rotatably mounted thereon by amounting shaft, said spinning tool having an arm radially extending fromthe axis of said mounting shaft and a spinning roller on said arm havingits axis angularly disposed relative to the shaft axis, said rollerbeing adjustable along the arm and rotatable about its axis, saidWorksupporting table and said spinning head being relatively movable onsaid standard toward and away from each other, said table having mountedthereon a work-supporting mandrel with an opening formed therein havingan axis adapted to be aligned with the axis of said shaft, said tablealso having a clamping mandrel adapted to be positioned over saidsupporting mandrel and having an outwardly projecting flange adapted tobe concentrically disposed with said opening in the supporting mandrel.

3. A spinning machine for the fabrication of hollow sheet metalT-flttings comprising a spinning head and a Wor '-support ng unit, said'spinning head including an arm extending radially from a supportingshaft and supporting a spinnin roller with its axis at an angle relativeto the shaft, said work-supporting unit and said spinning head beingrelatively movable in the direction of the shaft axis, saidwork-supporting unit comprising a supporting mandrel with its axisdisposed transversely of the shaft axis and having an opening with itsaxis adapted to be aligned with the shaft axis, and a clamping mandreladapted to be positioned over said supporting mandrel and having anoutwardly projecting flange adapted to be concentrically disposedrelative to said opening in the sup-. port'mg'mandrel.

References Cited in the file of this patent UNITED STATES PATENTS

1. A SPINNING MACHINE FOR THE FABRICATION OF TUBULAR SHEET METALT-FITTINGS COMPRISING A SPINNING HEAD ATTACHED TO A VERTICAL SUPPORTINGSTANDARD AND A WORK SUPPORTING TABLE MOUNTED ON THE SAID VERTICALSUPPORTING STANDARD, SAID SPINNING HEAD HAVING A SPINNING TOOL ROTATABLYMOUNTED THEREON BY A VERTICALLY DISPOSED MOUNTING SHAFT, SAID SPINNINGTOOL HAVING AN ARM RADIALLY EXTENDING FROM SAID MOUNTING SHAFT AND ACYLINDRICAL SPINNING ROLLER ANGULARLY DISPOSED TO SAID ARM, SAID ROLLEREXTENDING DOWNWARDLY FROM SAID ARM AND OUTWARDLY FROM THE CENTRALVERTICAL AXIS OF SAID MOUNTING SHAFT, SAID ROLLER ALSO BEINGLONGITUDINALLY SLIDABLY MOUNTED ON SAID ARM AND FREELY ROTATABLE ABOUTITS INCLINED AXIS, SAID WORK SUPPORTING TABLE AND SAID SPINNING HEADBEING MOVABLE VERTICALLY RELATIVELY, SAID TABLE HAVING REMOVABLYATTACHED THERETO AN ELONGATED LONGITUDINAL TUBULAR WORK SUPPORTINGMANDREL WITH AN ANNULAR OPENING VERTICALLY POSITIONED THEREININTERMEDIATE ITS ENDS, SAID TABLE ALSO HAVING AN ELONGATED SEMICIRCULARCLAMPING MANDREL POSITIONED ON THE SUPPORTING MANDREL AND HAVING ANUPSTANDING CYLINDRICAL SHAPING FLANGE VERTICALLY DISPOSED TO SAIDMANDREL, SAID CLAMPING MANDREL BEING POSITIONED OVER SAID SUPPORTINGMANDREL WITH SAID OPENING IN THE SUPPORTING MANDREL AND THE FLANGE OFSAID CLAMPING MANDREL CONCENTRICALLY ALIGNED WITH THE VERTICAL AXIS OFTHE SAID MOUNTING SHAFT.